Presentation 2008-11-06
An OFDMA Signal Transmission System with SAW Chirp Filters : A mobile satellite communication with next generation cellular system(Satellite System II)
Osamu Ichiyoshi, Takaya Watanabe,
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Abstract(in Japanese) (See Japanese page)
Abstract(in English) The OFDM is the signal transmission method adopted for most of the next generation cellular mobile communication systems such as WiMAX, OFCDM and Advanced PHS. The OFDM poses three technical difficulties for development of hand-held terminals. The first problem is the heavy signal processing load required for the FFT and IFFT operations. The second problem is that the pair of IFFT and FFT operations is not applicable to SCPC (single-channel-per-carrier) mode of operations which should be most suitable for hand-held terminals. The third problem is the technical difficulty in detection of the guard interval (GI) timings at the receiver under the heavy interference conditions with different timings in cellular systems. We propose a perfectly synchronized OFDMA system and equipments with SAW chirp filters to solve those problems above stated. The OFDMA is such an expansion of the OFDM that each terminal can operate in SCPC/FDMA modes and the whole signals combined in the space form the equivalent OFDM signals. The whole terminals must function in perfect symbol timing synchronization to form the equivalent OFDM signals format. Then a SAW chirp filter can be used to conduct the Chirp-Z transform that achieves the pulse compression and separation of the receive OFDM signals on the time domain. As the signal separation is made by the SAW device the heavy signal processing load for FFT is totally eliminated. The OFDM signal transmission can be also made with the SAW filter that functions the Inverse Chirp-Z transformation. Then a complete OFDM communication station can be realized even for hand-held terminals. The terminal can also operate in SCPC/OFDMA modes. Another feature of the system enables an FDM-CDMA, which allows one frequency re-use and soft hand-over operations for the cellular systems and also a universal expansion of the service areas through existing mobile satellite communication systems. The perfect timing synchronization is the key function for the proposed system. Some simple methods for detection of the timing errors for the OFDM in both FFT and the proposed SAW Chirp-Z transform system are proposed. We also propose a perfectly synchronized base stations network that can readily solve the GI detection problem.
Keyword(in Japanese) (See Japanese page)
Keyword(in English) OFDM / OFDMA / SAW / Chirp / Chirp-Z transform / FFT / FDM-CDMA / SCPC / Cellular communication
Paper # SAT2008-28
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Committee SAT
Conference Date 2008/10/30(1days)
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Registration To Satellite Telecommunications (SAT)
Language ENG
Title (in Japanese) (See Japanese page)
Sub Title (in Japanese) (See Japanese page)
Title (in English) An OFDMA Signal Transmission System with SAW Chirp Filters : A mobile satellite communication with next generation cellular system(Satellite System II)
Sub Title (in English)
Keyword(1) OFDM
Keyword(2) OFDMA
Keyword(3) SAW
Keyword(4) Chirp
Keyword(5) Chirp-Z transform
Keyword(6) FFT
Keyword(7) FDM-CDMA
Keyword(8) SCPC
Keyword(9) Cellular communication
1st Author's Name Osamu Ichiyoshi
1st Author's Affiliation Human Network for Better 21 Century()
2nd Author's Name Takaya Watanabe
2nd Author's Affiliation World Technology Instrument Co., Ltd
Date 2008-11-06
Paper # SAT2008-28
Volume (vol) vol.108
Number (no) 274
Page pp.pp.-
#Pages 6
Date of Issue